Officially, AArch64 is the name of the 64-bit execution state. The instruction set is called A64, to contrast it with the pre-v8 instruction sets A32 and T32 (f

Officially, AArch64 is the name of the 64-bit execution state. The instruction set is called A64, to contrast it with the pre-v8 instruction sets A32 and T32 (formerly known as Arm and Thumb). That said, in practice many people use them interchangeably since A64 is the only instruction set available in AArch64.